1. Field of Invention
This invention relates to bowling equipment and is particularly directed to improved bowling balls and methods of manufacturing said balls.
2. Prior Art
The sport of bowling has been popular for hundreds of years and there are numerous variations of the sport. One of the most popular versions is the game of Ten Pins, which employs a ball weighing approximately 10-16 pounds. These bowling balls are usually provided with holes, into which one or more of the bowler's fingers are inserted, to facilitate the bowler's grip on the ball and to assist in controlling or steering the ball. Two- or three-holed bowling balls are the most common. With two-hole bowling balls, the holes are positioned to accommodate the bowler's middle and third fingers, while three-hole balls provide an additional hole for the bowler's thumb. Obviously, the size, location and spacing of such holes must be varied to correspond to the size of the bowler's fingers, the span of the bowler's hand and the bowler's individual bowling style. Serious bowlers are often extremely critical of these matters and demand that their bowling balls be custom-made to provide the desired grip and control. Traditionally, bowling balls haven been made of molded rubber or plastic and the finger holes have been drilled into the balls, subsequently, by the retailer. The finger holes are usually straight and are drilled generally perpendicularly to the surface of ball to extend radially inward. However, when gripping, human fingers tend to curve and many prior art methods and apparatus have been proposed to accommodate such curvature in forming the holes of bowling balls. It has been proposed to drill relatively large diameter holes in a bowling ball and to provide customized inserts which could be formed to correspond to the size, shape and desired curvature of a given individual. However, this technique often adversely effects the weight and balance of the bowling ball and these factors are frequently irregular from one ball to the next. Furthermore, the prior art methods and apparatus for customizing bowling ball finger holes often add considerable expense to the cost of the bowling ball and sometimes require frequent maintenance. A search in the United States Patent Office has revealed the following:
______________________________________ U.S. Pat. No. INVENTOR ISSUED ______________________________________ 5,002,277 P. G. Ontko Mar. 26, 1991 4,632,396 W. G. Taylor Dec. 30, 1986 2,703,712 R. C. Obenchain Mar. 8, 1955 3,401,935 R. R. Dietz Sept. 17, 1968 ______________________________________
However, each of these references is subject to the limitations discussed above. Thus none of the prior art bowling balls and production methods have been entirely satisfactory.